This invention relates to a tunnel or road header apparatus for excavating or driving an underground roadway by a tunneling operation. The apparatus is equipped with a caterpillar running gear for moving along the roadway being excavated and a portal frame having a horizontal track which extends transversely of the longitudinal direction of machine movement along the roadway being driven. A cutter head is displaceably guided on the horizontal track for engagement with the tunnel face.
German patent specification No. 22 48 785 discloses a drifting and cutting machine equipped with a caterpillar running gear carrying a portal frame. This frame includes a cross member which extends transversely of the longitudinal direction of the roadway and carries a percussion tool held by a boom which is mounted so as to be three-dimensionally pivotal and rotatable about its longitudinal axis. The percussion tool is movable transversely of the longitudinal direction of the roadway on the cross member of the portal frame. Two other cross members are arranged parallel to one another on the portal frame and are spaced apart in the longitudinal direction of the face, and the mining equipment is traversable on the cross members.
German patent specification No. 12 34 170 discloses a road-driving machine comprising a machine frame which is displaceable in the longitudinal direction of the roadway being driven and a shearer head projecting toward the rock face. The shearer head is held by a guide rail which extends transversely of the roadway longitudinal direction over the width of the road. Two arms in the form of a link parallelogram carry the guide rail and are adjustable over the height of the roadway tunnel. The shearer head is mounted displaceably on the guide rail and can be guided over the entire roadway tunnel cross section.
While the system according to the first citation mentioned above allows completely free access to the rock face over the entire roadway width so that it is possible to remove the spoil by means of a loader traversable independently of the drifting machine, the system according to the latter citation requires a conveyor extending over the roadway width to receive the spoil. In both cases, therefore, the devices which carry the breaking tool or its guide rail are relatively far away from the rock face due to the long reach of the percussion tool or the transverse conveyor means required to remove the spoil.